The Coiffure on Phillips sold a thousand of those deals in just 12 hours. Salon owner Lori Williams says she learned after offering her first deal to extend the expiration date so the salon isn't overbooked and the customer out of luck and money.

"We've made sure that doesn't happen. We feel if they purchased Groupon, they're entitled to service. We have done everything we can to make sure people get it," Williams said.

Now when Coiffure sold so many deals on the group couponing site, it extended deadlines for cashing them in. But businesses don't have to do that.

Classified Verticals runs KELOLAND's Spotlight Deal of the Day. Petersen says in addition to keeping track of expiration dates, consumers need to realize that taxes and tips may be extra charges not covered by the voucher.

"If you go in and receive good service from a restaurant or another business that thrives on tips, you should tip on full value," Petersen said.

Petersen says KELOLAND Spotlight is rolling out new electronic redemption tools for businesses to keep better track of how many vouchers are being cashed in. Williams says customers often don't realize they have to have the printed voucher in hand.

"There's some misconceptions about Groupons as well, that we are getting all that money. They have to print out Groupon and bring it into establishment. Otherwise, we don't know if they've used it or not," Williams said.

Petersen says technology is coming to make the transaction even easier.

"Instead of having to carry around five printed vouchers, hopefully soon, we'll be able to roll that out and merchants will be able to take electronic form of redemption," Petersen said.

Another legal issue that has come up is whether deal sites are more of a coupon or a gift card. Federal law says gift cards can't expire for at least five years. But vouchers do have expiration dates of just a few months to up to a year. The issue has led to three class-action lawsuits across the country, all of which are pending.